Project Summary All cancer patients live with the possibility that their cancer will recur and many patients develop secondary cancers as a result of treatments used for their original cancer. This project addresses the problem of drug resistance and disease recurrence in cancer by leveraging unique, single nanoparticle techniques to identify rare, often ?hidden?, drug-resistant cells in leukemia patients and to determine effective drug combinations to eradicate cancer recurrence. Our goal is to develop a robust Single Cell PhosphoCount (SCPC) platform that can profile blood cells from individual leukemia patients with unprecedented molecular-level sensitivity (single phosphoproteins [PPs]) using minimal cell samples (250-5,000 cells). The SCPC technology not only reveals the presence of rare drug-resistant cells with high sensitivity but also guides therapeutic options by enabling screening of drug combinations for completeness of PP- inhibition in individual patients. PP-activity is modulated by kinase inhibitor [KI] therapeutics ($27B by 2018) but is extremely challenging to accurately detect in single cells due to their low abundance and diminished levels following KI treatment. Current technologies lack the molecular sensitivity to reliably measure PP response in single cells and also require large number of cells to conduct KI-combination screening of patient samples. The SCPC PP detection sensitivity surpasses FACS and mass spectrometry (up to x10 higher signal to noise) and has minimal post-assay cell loss (99% cell retention at 500-5k cells). SCPC has detected rare cells (< 9%) in leukemia patients that are PP-insensitive to KI treatment by direct PP interrogation, a feat that has not been accomplished in routine practice. SCPC has also successfully characterized single leukemia cell PP-response heterogeneity and ranked a panel of FDA-approved KIs by completeness of PP-inhibition. Phase I funds will be used to establish cell standards of SCPC system reproducibility and demonstrate the capability of the SCPC to rank combinations of KIs by their completeness of PP-inhibition in cell populations from individual leukemia patients, a capability not currently available for clinical samples. This will lay the foundation for a Phase II proposal to replicate SCPC systems and conduct an expanded study with cancer patient samples. The research team consists of the innovator and developer of nanoparticle imaging technologies (co-PI: Vu), and an established, small business with success in obtaining rights to, and managing and developing early stage biomedical technologies (Virogenomics BioDevelopment Inc. (VBD), co-PI King). The SCPC platform leverages innovative intellectual property - single probe counting strategies and quantum dot proteomic technology (1 awarded patent, 2 pending). VBD has an option agreement to exclusively license the SCPC technology. Opinion leaders at leading cancer institutions interested in the clinical diagnostic applications of the SCPC provide letters of support.